1. Field of the Invention
The present invention relates to a method of partially attaching an additional attaching material for various types of printed circuit boards, and more particularly to a method of attaching an electromagnetic interference (EMI) metal plate or a protection film after printing circuits on a circuit block of the printed circuit board or coating an insulating layer, so as to save manufacturing time and avoid misalignment.
2. Description of the Related Art
Rigid printed circuit board is also known as rigid board, which is a basic carrier for electronic products in the industries of information, electronics, communications, consumer electronics, aerospace, and national defense, etc. These products are developed and manufactured in a trend of small diameter, high density, multilayer and small circuit.
On the other hand, flexible printed circuit board is also know as flexible printed circuit (FPC) which has the light, thin, small, bendable, low-voltage and low consuming power properties. Since the shape of these products can be changed according to the required spatial design and these products are bendable and EMI-resisting, therefore their size and weight can be reduced greatly, and the flexible printed circuit boards have replaced traditional rigid boards progressively and are used extensively in many different commercial areas such as satellites and medical treatments, etc. In the recent decade, information and consumer electronic products are developed rapidly, and both consumption and quality of the flexible boards grow rapidly under the user requirements for small volume and light weight. At present, local manufacturers primarily manufacture single-sided and double-sided panels for notebook computers, mobile phones, liquid crystal displays, optical disk drive, and digital cameras, etc.
To meet the requirements of the area and the circuit density for various different light, thin, short and compact products (such as mobile phones and liquid crystal displays), manufacturers generally combine and mix flexible and rigid printed circuit boards for their applications.
Regardless of a rigid, flexible or mixed mode of the printed circuit board, a plurality of circuit blocks are arranged on a printed circuit board, depending on the size of the circuit block of the printed circuit board or manufacturing requirements. After a circuit layer is produced onto a circuit by lithography, it is necessary to coat a layer of protection film or cover an electromagnetic interference (EMI) metal plate onto the circuit block to achieve the effects of preventing copper wires from being oxidized, protecting the circuit block from being affected by humidity, and enhancing the durability of the circuit. However, these protection films are very soft or small, and thus it is very difficult to cover the circuit block flatly and uniformly by the protection films. Skillful operators are required for aligning and covering the blocks one by one, and thus the conventional manufacturing method cannot be used for automation and mass production, and the manufacturing remains very high.